1. Field of the Invention
The present invention relates to a novel X ray image recording system. In one aspect, the invention relates to the permanent recording of images or objects on a sensitive surface by irradiation with X rays or other radiations of shorter wavelengths. In another aspect, the invention relates to a new image recording substrate sensitive to radiation with wavelengths shorter than fifty angstroms. In still another aspect, the invention relates to a new and novel X ray photographic process in which an image is reproduced without the conventional developing step.
2. Discussion of the Prior Art
Present recording systems for X rays use mostly silver halide emulsions. The world consumption of X ray films exceeds that of amateur and industrial photography. The amount of silver in X ray material is far greater than for ordinary photography, and the recent increase in the price of silver has already affected the consumer.
A variety of silver based radiographic films or papers adapted for various applications are found on the market. They are produced by major photographic companies such as Eastman Kodak, Dupont, Agfa Gevaert, Ilford, Fuji, etc. Medical radiography uses mostly films giving negative images, paper finds application in industrial radiography and gammagraphy.
Xerographic systems for radiography have been introduced recently. They are presently the only practical alternative for silver halide radiography. The method utilizes selenium plates instead of the conventional drum used in xerographic photocopy. Such plates, which have been previously electrostatically charged, are exposed to the X ray image in the absence of light, and transferred into a development machine which applies toner selectively on the plate and then transfers and fixes the toner image onto a glossy bristol paper or a plastic film. Radioxerography has a sensitivity approaching that of silver halide radiography. It generally provides a positive image on an opaque substrate, which creates a problem for physicians who are accustomed to negative transparencies. It is, nevertheless, gradually accepted in the medical world.
Radioxergaphy, like xerographic photocopy, offers the advantage of dry processing, but at the cost of more expensive and cumbersome equipment requiring specialized maintenance.